From: David ‘Bombe’ Roden <bombe@pterodactylus.net>
Date: Sat, 5 Jul 2008 04:40:33 +0000 (+0200)
Subject: add growing buffer
X-Git-Tag: 0.1~59
X-Git-Url: https://git.pterodactylus.net/?p=ecparse.git;a=commitdiff_plain;h=b24b03abb90553821d627e87dac5ec07d81fd09c

add growing buffer
---

diff --git a/GrowingBuffer.cpp b/GrowingBuffer.cpp
new file mode 100644
index 0000000..492f244
--- /dev/null
+++ b/GrowingBuffer.cpp
@@ -0,0 +1,79 @@
+/**
+ * © 2008 by David ‘Bombe’ Roden <bombe@pterodactylus.net>
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include "GrowingBuffer.h"
+
+GrowingBuffer::GrowingBuffer(size_t initialSize) {
+	this->data = malloc(1024);
+	this->size = 1024;
+	this->limit = 0;
+	this->position = 0;
+}
+
+GrowingBuffer::~GrowingBuffer() {
+	if (this->data) {
+		free(this->data);
+	}
+}
+
+size_t GrowingBuffer::getPosition() {
+	return position;
+}
+
+size_t GrowingBuffer::getLimit() {
+	return limit;
+}
+
+size_t GrowingBuffer::getSize() {
+	return size;
+}
+
+void GrowingBuffer::seek(size_t position) {
+	this->position = (position > limit) ? limit : position;
+}
+
+void* GrowingBuffer::read(void* buffer, size_t length) {
+	size_t bytesToCopy = (length > (limit - position)) ? (limit - position) : length;
+	memcpy(buffer, (char*) data + position, bytesToCopy);
+	position += bytesToCopy;
+	return buffer;
+}
+
+void GrowingBuffer::write(const void* buffer, size_t length) {
+	if (length > (size - position)) {
+		int newSize = size;
+		do {
+			newSize *= 2;
+		} while (length > (newSize - position));
+		void* newData = malloc(newSize);
+		memcpy(newData, data, position);
+		free(data);
+		data = newData;
+	}
+	memcpy((char*) data + position, buffer, length);
+}
+
+void GrowingBuffer::truncate() {
+	limit = position;
+}
+
+void GrowingBuffer::clear() {
+	position = 0;
+	limit = 0;
+}
+
+void GrowingBuffer::resize(double factor) {
+	if (factor < 1.0) {
+		factor = 1.0;
+	}
+	if (size != (limit * factor)) {
+		void* newData = malloc((size_t) (limit * factor));
+		memcpy(newData, data, limit);
+		free(data);
+		data = newData;
+	}
+}
+
diff --git a/GrowingBuffer.h b/GrowingBuffer.h
new file mode 100644
index 0000000..894267d
--- /dev/null
+++ b/GrowingBuffer.h
@@ -0,0 +1,51 @@
+/**
+ * © 2008 by David ‘Bombe’ Roden <bombe@pterodactylus.net>
+ */
+
+#pragma once
+
+/**
+ * A buffer that will grow to accomodate the data being put into it.
+ */
+class GrowingBuffer {
+
+public:
+
+	/**
+	 * Empty constructor. Creates a buffer with a default size of 1024 bytes.
+	 *
+	 * @param initialSize The initial size of the buffer in bytes
+	 */
+	GrowingBuffer(size_t initialSize = 1024);
+
+	/**
+	 * Destructor. Frees all used resources.
+	 */
+	~GrowingBuffer();
+
+	size_t getPosition();
+	size_t getLimit();
+	size_t getSize();
+
+	/**
+	 * Sets the position of the buffer. The next {@link read(void*, size_t)} or
+	 * {@link write(const void*, size_t)} operation will be applied at the new
+	 * position.
+	 *
+	 * @param position The position to seek to
+	 */
+	void seek(size_t position);
+	void* read(void* buffer, size_t length);
+	void write(const void* buffer, size_t length);
+	void truncate();
+	void clear();
+	void resize(double factor = 1.0);
+
+private:
+	void* data;
+	size_t size;
+	size_t limit;
+	size_t position;
+
+};
+